Fabtech?s 6" 4 Link Conversion system for the Ford F450 and F550 Super Duty is built to handle the on and offroad demands of the truck enthusiast. This vehicle?s suspension is more robust than the Ford F250 and F350 and therefore demands specialty parts only available from Fabtech. This system comes with everything needed to convert to a 4 Link front suspension. The system will provide less caster change throughout the travel range which benefits on road driving. Offroad the 4 Link system will provide more articulation than a Radius Arm for increased terrain traversing at all speeds. Fabtech?s 4 Link System has been proven in over 10 years of service in consumer, commercial and military applications. High quality components with properly design suspension geometry is the pinnacle of Super Duty suspension systems. Each Fabtech component is expertly built in house and has specific design features and benefits as listed below. FEATURES: LINK ARMS & BRACKETS - 2" OD Heavy wall link arms have 1/4" thick steel brackets at the axle with adjustable alignment cams and Fabtech?s legendary 5 Ton joints? to pivot at the frame for an extended service life. The 5 Ton joints? have been proven in military use for over 10 years and are quiet and strong. The 4 Link Arms attach to stout 1/4" thick steel frame brackets for a solid mounting of the new suspension. The geometry of the 4 Link arms and frame brackets has been designed to provide an improved highway ride due to reduced caster change and able to tackle rough offroad conditions better than a Radius Arm suspension. DIRT LOGIC 4.0 CONVERSION - Simplistic super stout 1/4" thick steel brackets utilize the factory coil bucket to bolt in the big Dirt Logic 4.0 Coilover. A massive 4" diameter stainless steel body with 1.25 NitroSteel? piston rod for maximum corrosion resistance and durability for the most aggressive driving conditions. American made coil springs handle the weight of the F450 or F550 and provide a superior ride